Fluid tanks typically have high strength requirements because of the weight of the fluid or the pressured gas to liquid stored in the tanks. Thus, some tanks are constructed from metal. These metal tanks typically have various pieces that are welded together to form the tank. This welding may be effectuated by placing a person on the inside of the tank during the tank construction and having the person inside the tank weld the pieces together such as disclosed in U.S. Pat. No. 6,161,179 to Madison, the contents of which is incorporated herein by this reference.
Tank interiors qualify as confined spaces and are subject to regulations of the Occupational Safety and Health Administration (OSHA). As known in the art, a person working in a confined space is more susceptible to injury, illness and even death. For instance, the confined space may subject the worker to dangers from explosion, poisoning and asphyxiation. Tank manufacturers, thus, must take appropriate steps and safety precautions to guard against these hazards pursuant to the OSHA regulations, including providing respirators and other safety equipment that is not required for external welding. Implementation of these appropriate steps and safety precautions by the tank manufacturer add both time and money costs to tank construction.
Further, many tanks are constructed of materials that may corrode or rust during use. Thus, these tanks may be lined with a corrosion resistant liner, such as that disclosed in U.S. Pat. No. 6,431,387 to Piehler, the entirety of which is incorporated by this reference. Some liners may be applied by spraying a coating of liner material on the inside of the tank. The addition of the liner adds expense and time to the manufacturing process and, thus, increases the cost of the tank to the ultimate consumer. Since the application of a liner adds more work in a confined space, the incorporation of the liner may further subject the tank manufacturer additional expense and safety issues as well as governmental regulations.
Thus, a more efficient process of manufacturing a tank and the tank resulting therefrom would constitute an improvement in the art.